This invention relates to burners for electric arc furnaces, ladles and other type metal and other product melting furnaces for high temperature heating work products, and the like, wherein fuel and oxygen are mixed to form a high-velocity flame. More particularly, the invention relates to an oxy-fuel burner of the rocker burner type which includes a combustion chamber recessed into a graphite burner block, where the fuel is supplied to the walls of the combustion chamber for film cooling, and wherein the burner block includes a plurality of parallel cooling bores arranged in an array about the combustion chamber so as to reduce the temperature of the burner block and the combustion chamber.
High-velocity or "rocket" burners are utilized in high temperature conditions and in conditions where it is desirable to direct a flame toward a given area. The high velocity of the flamegenerates a loud noise, and the high temperature of the flame raises the temperature of the burner to a level that tends to rapidly deteriorate the burner. In some applications, it is desirable to cut off the supply of oxygen and fuel to the burner while the work product in the burner is still hot or is still continuing to be heated by other heat sources. Under these circumstances, the burner is subjected to heat emitted from the work product and from the other heat sources and the burner continues to deteriorate.
In the past, various steps have been utilized to avoid the deterioration of high-temperature burners in furnace atmospheres. For example, some burner designs include water cooling features, whereby water is rapidly circulated at high volumes so as to extract heat from the burner. This tends to avoid rapid oxidation and other deterioration of the burner. During the operation of some furnaces the burners are physically withdrawn from the furnace chamber when the burner is not fired so as to avoid prolonged exposure of the burner to the heat emitted within the furnace. In other furnaces the idle burners are not physically withdrawn from the furnace chamber but a supply of air is moved through the idle burner and into the furnace so that the air cools some of the exposed surfaces of the burner.
While some of the foregoing features have been successful in prolonging the lives of high-temperature, high-velocity burners for furnaces, certain problems have not been overcome. For example, when an idle burner is withdrawn from the furnace, a certain amount of heat and noise is emitted from the furnace, and the burner must be designed so that it can be withdrawn. Also, when air is supplied through an idle burner to cool and protect the burner, the added air in the furnace tends to change the chemistry of processing. Also, the use of water to cool a high-temperature burner is somewhat hazardous in that if a crack should occur in the burner or if water flow is interrupted or if some other condition in the burner should occur that causes water to leak into the confines of the burner or into the furnace, an explosion will occur.